Aminolysis of 2,2,2-Trichloro-1-arylethanones in Aprotic Solvents

Article abstract of DOI:10.1021/jo00281a015

The kinetics of the reaction of the title substrate with various alkylamines was studied in n-heptane, dichloromethane, dioxane, tetrahydrofuran, and acetonitrile.The reaction was third-order in amine when the solvent was n-heptane or dichloromethane.In the other solvents a second-order dependence on was observed.The fourth-order rate constants for the reaction of n-butylamine with various 2,2,2-trichloro-1-arylethanones in dichloromethane yielded a ρ value of 3.0.In all solvents the observed rate constans decreased with a temperature increase.Two mechanistic possibilities were suggested, the first one in solvents of low donicity, involving a T⁰ intermediate formed in a concerted process with the participation of an amine dimer; and the second one, a stepwise process in more basic solvents which takes place via a T^+/- intermediate.Base-catalyzed collapse of the tetrahedral intermediates is the rate-determining step in both pathways.